VPS means Virtual Private Server it allows many Virtual Servers to run or to work within one physical server. Every VPS has its own portion for the resources,
For example if a server is having a specification of x GB of RAM, and y GB of hard disk. So in that case few mb of RAM and few GB will be available to a proper VPS. This mean that what resources the other VPS server is using, that amount particular amount of hard disc and RAM will always be there for use.
There are many VPS control panel some of them are as follow
Xen, Virtuozzo, Vmware, etc
There are several disadvantages in Virtual Private Server like,
Management of server, cost, value for money
Cost: This is the factor that is very necessary to be conceder like, cost of the cloud VPS hosting is such high that puts so many people off from the use of cloud VPS hosting